At relatively cold ambient temperatures diesel fuel can partially solidify (gel) due to the formation of waxy crystals. Gelling of the fuel can affect engine performance, including causing the engine to cease operation. Formation of the waxy crystals causes the fuel to become cloudy. The cloud point temperature of the fuel is the temperature at which the wax crystals begin to form. The cloud point temperature of diesel fuel can vary widely even within fuel of the same grade (i.e., No. 2 diesel), and also varies widely when biodiesel fuels are mixed with diesel fuel. Diesel fuels are generally blended so as to have a cloud point temperature which is appropriate for the location in which the fuel is sold. Therefore, it may be desirable to detect and monitor the cloud point temperature of the diesel fuel, since vehicles may take on fuel in a relatively warmer region where gelling is not a concern and due to their long travel range carry the fuel blended for the warmer region to relatively colder regions where gelling is possible. A problem associated with some existing cloud point monitoring devices is that wax crystals can form in such a way that they may not be detected in the diesel fuel, resulting in an inaccurate determination of the cloud point temperature, thereby limiting the ability to take appropriate measures to prevent gelling of the diesel fuel.
Accordingly, it is desirable to develop cloud point monitoring systems having improved accuracy with regard to detection and monitoring of the cloud point temperature.